Side curtain airbags have been added as an additional measure of passenger safety in automobiles. A side curtain airbag assembly is retained behind interior trim of the headliner, just above the vehicle side window. During a crash event, the airbag is deployed between the vehicle occupant and the window or other side structures of the vehicle.
A fastener for holding a side curtain airbag in place must be strong enough to retain the airbag assembly in place even during aggressive, rapid deployment of the air bag during a vehicle crash event. It is necessary also to retain a side curtain airbag assembly in a fixed position without rattling during vehicle operation. Desirably, the fastener can be inserted quickly and easily in a simple operation, yet has strong retention force. Still further desirable is a fastener assembly that is conducive to pre-assembly steps so that final installation of the airbag assembly can be performed quickly and efficiently.
A known fastener assembly for side curtain airbags includes a bolt and a weld nut of standard design. In addition to providing an opening by punching or stamping a frame-like member of the vehicle roof structure, it is necessary to position and secure, such as by welding, a nut in the correct location. This requires an additional manufacturing step for welding the nut in place, in addition to the subsequent securing steps for installing the airbag assembly in position. The assembly steps required for installing the airbag assembly can be time consuming and complex, including positioning the bag in the proper location and separately acquiring a bolt, inserting the bolt through the bag assembly, and rotating the bolt into the nut that was welded in place in the roof structure during a previous step. A fixation method of this type is robust, but can be expensive in materials and assembly costs. Further, it is necessary to fix a standard bolt in the tightened position so that vibrations during subsequent operation of the vehicle do not cause the bolt to work loose, backing out of the weld nut.
In some installation and assembly processes, it is desirable to acquire and record data documenting that all fasteners have been properly positioned, properly tightened and properly verified. In a standard bolt and nut attachment, some degree of verification can be achieved through visual inspection and by acquiring torque readings for the tightened fastener. However, an improperly inserted fastener can exhibit the expected high torque readings even when not properly tightened in place. Further, with a standard bolt there has been no satisfactory way of ensuring that the individual readings recorded for verification have each been acquired from different fasteners. Multiple readings can be acquired from a single fastener, either intentionally or inadvertently.
Issues such as those noted above and others have been present in the assembly and installation structures and processes for installing fastener assemblies used to attach side curtain airbags in automobiles. Accordingly, improvements in fastener assembly structures, installation processes and installation verification procedures are desirable and advantageous.